You should either have a relay in there somewhere , just follow the wiring untill you find it , also its possible they put a temperature sensor on it , and that its not working for some reason.My guess its a relay blew on you.

1996 Jeep Grand Cherokee 5.2 with mods.Hughes Air gap intake , 52MM TB , ford injectors, 2 3/4" lift, Doug Thorley headers , HID headlights with LED , HID fog lights , glow gauges , a few others